basically you got 4 options
light tanks - BT-7, A-20, leopard. those are basically scout, very fast & agile but light armored and easily killed. good to scout ahead of the main force, harass enemy lines and artillery. these tanks usually die EACH game in the first few minutes but when they fulfilled their duty they are a great asset to the team. killing or spotting enemy artillery so you own team artillery cna take them out is a huge blow to the strengh of the enemy team.
artillery - the coward sniper in the back of the map hiding in a bush waiting for targets to pop up. most hated class in the game. their huge howitzer guns can take out any light-medium tank in 1 or 2 shots. even heavy tanks have to fear these when they continue to mount even bigger guns later on. draw backs are low health & armor, extreme long relaod and once scouted they are prime target. teir lack of turret and slow relaod makes them easy pray in close quaters.
medium tanks - you panzer IV and T-34, great skirmish tanks, fast and agile enough to out flank most heavy tanks and tear open the flanks of the opposite team. when hunting in small packs they are a force to reckon with. they are good at everything but excel at nothing in particular.good speed , decent armor, often quite good guns, and enough health to take a few hits.
heavy tanks - long range sniper with strong armor, should stay a bit behind the medium tanks but sometimes is needed on the frontline to make a breakthough. strong armor huge amount of health and can mount the big guns. god on their own but can be overwhelmed by many mediums or focused fire. better stay in a group and "lead" the team, preferable from "behind". your armor might be strong but you are not invincible, there is ALLWAYS someone with a bigger gun.
tank destroyers - strong frontal armor, low profile and can often mount the biggest guns in their class. they lack a turret and mobility. when outflanked by faster medium/light tanks they suffer greatly without support. but they are also great for support their long range high caliber guns can pick off most targets. so they are great for supporting a heavy tank from behind or a wolfpack of mediums. also good on defense to defend your base and artillery. they also have small camouflage bonus while firing their gun. they dont get revealed as easy as other tanks.
soo if you want to "try" scout OR medium tanks i can recommend the RUSSIAN mediam tank tree.
MS-1 -> BT-2 ->BT-7 -> A-20 (best russian light scout tank) -> T-34 ...
specially to way to the T-34 is quickly done. and on the way you get a takes of light tanks too.
if you rather try medium or heavy tank try the german tree.
leichtracktor -> panzer II -> panzer III a -> panzer III -> panzer IV or Panzer III/IV depending on what your goal is by then
heavy tanks or panther.
for tank-destroyers i recommend the german tree, they mostly have better guns and more armor than their russian counter part. but besides the stug the russian are more mobile.
if you are SURE you want to go heavy russian heavy tree give you the KV very early. and the IS series is very strong.
